Apparatus for applying labels or plates to blow molded thermoplastic hollow bodies

ABSTRACT

A wrap-round label is applied to a blow-moulded article by means of a plunger extending through the mould wall. The front face of the plunger is concave, being shaped to fit the article, and the label is initially mounted on the plunger so as to be stretched or taut across the front face. When blow-moulding commences, initially the plunger is in an outwardly retracted position. As blow moulding proceeds, the plunger is advanced so as to wrap the label around the article.

United States Patent Langecker [54] APPARATUS FOR APPLYING LABELS ORPLATES TO BLOW MOLDED THERMOPLASTIC HOLLOW BODIES [72] Inventor: ErhardLangecker, Hohbuschener Weg 5, Meinerzhagen/Westphalia, Germany [22]Filed: June 1, 1970 [21] Appl. N0.: 42,064

[52] US. Cl ..425/122, 425/ 126 [51] Int. Cl. ..B29c 17/07, B29d 23/03[58] Field of Search ..18/5 BL [56] References Cited UNITED STATESPATENTS 3,151,193 9/1964 Thornton ..l8/5 BL X 3,324,508 6/1967 Dickinson..l8/5 BL 3,292,209 12/1966 Borkmann ..l8/5 BL [451 Aug. 15, 1972FOREIGN PATENTS OR APPLICATIONS 245,545 7/ 1963 Australia ..l8/5 BLPrimary Examiner-L Spencer Overholser Assistant Examiner-Ben D. ToborAttorney-Watson, Cole, Grindle & Watson [57] ABSTRACT A wrap-round labelis applied to a blow moulded article by means of a plunger extendingthrough the mould wall. The front face of the plunger is concave, beingshaped to fit the article, and the label is initially mounted on theplunger so as to be stretched or taut across the front face. Whenblow-moulding commences, initially the plunger is in an outwardlyretracted position. As blow moulding proceeds, the plunger is advancedso as to wrap the label around the article.

6 Claims, 12 Drawing Figures PATENTEDAUB 1 5 m2 SHEET 1 BF 6 ram 0 v wmm A 1m 7m r 5% y B Mar PATENTEDAUS 15 I872 SHEET 2 [1r 6 APPARATUS FORAPPLYING LABELS OR PLATES TO BLOW MOLDED THERMOPLASTIC HOLLOW BODIES Theinvention relates to a method of applying labels or plates to hollowbodies of thermoplastic synthetic substance produced by a blow mouldingprocess.

It is known to attach a colored and/or printed label of a thin film ofweldable or adhesive material inserted into a blow mould during the blowmoulding of the hollow body to that hollow body where the label isintroduced either from the outside through openings in the wall of theblow mould or from the inside through the parting line of the blowmould.

In the case of such attachment of a label or a plate to a hollow bodyproduced by blow moulding there exists an essential problem in that onapplying the label to the hollow. body the formation of the airinclusions between the hollow body and the label have to be avoided asfar as possible. For this purpose the surface of the label or platewhich comes into contact with the hollow body has been roughened inorder to distribute evenly the air which inevitably becomes entrappedbetween the label and the hollow body in the hollows formed by theroughening and in this way to avoid the formation of spot-like blisters.For the same purpose the labels to be applied have also been producedfrom tissue or of porous material or even of perforated foils. Even ifthese films can be applied substantially without the formation ofblisters, they have substantial disadvantages which are opposed to theiruse. These labels to be applied are always provided with pictures and aprinted text. In order to prevent damaging the printing by abrasion,transparent films are used which are provided with the printed text ontheir surface which is to be lain on the surface of the hollow body. Inthis case the roughening and the use of a tissue or a perforated film isdisadvantageous, since the clarity of the printed text is impaired bythe roughening which is on the surface. Furthermore, there is the dangerthat the hollows in the film surface due to the roughening or the use ofa tissue becoming filled by the printed ink so that there can occur atthe printed large surface places spot-like blisters, since thepossibility of a uniform distribution of the air is no longer ensured.The same holds true for perforated films. Also they can detrimentallyimpair the printed picture; likewise the perforations at the printedplaces can be closed by the ink so that even here the formation ofblisters is not reliably avoided.

Therefore in the interest of a clear reproduction of the text on thelabels it is desirable to use films as labels which render possible afaultless and clear application of the text and picture print. In aknown or previously proposed method there is displaceably mounted in theopening of the blow mould a plunger the face of which has a curvaturecorresponding to the curvature of the hollow body. The label to beapplied to the hollow body is inserted in any appropriate manner in theplunger, for example by hand or by stamping and is maintained in thecorrect position on its upper surface, where the plunger upper surfacecan be provided with suction bores to hold the label firmly. In thisway, the operation is carried out in such a manner that during theclosing operation of the blow .mould the plunger carrying the label ismoved in the mould closure position so that on inflation of the parisonthe label is to be found in its final position in relation to the hollowbody. ln this I into a hollow body at an angle of embrace of about 60 toand thus permits the implementation of the advantages given by thesmooth film.

This is effected in accordance with the invention in that the label withits edges lying in the direction of the axis of the hollow body is heldflexibly in a stretched position on the surface of a plunger which isadapted to the shape of the hollow body and in that the plunger is inresilient position in relation to the mould wall during the inflationand is advanced directly before the end of the inflation from itsresilient position into a mould closure position corresponding to thefinished hollow body, where the label envelops the hollow body and theair which is between the label and the parison is led off via theparting line of the mould. The invention resides in the realization thata blister-free application of a label to a hollow body is ensured onlywhen on contact of the hollow body with the label the latter comes torest firstly in the region of its center on the label so that betweenlabel and hollow body there are formed on both sides of the centerinterstices which enlarge in a wedge-shaped manner and which are made todisappear by the movement of the plunger into the mould surface withgradual diminution, where the label arrives at complete blister-freeemplacement on the hollow body, since the air in the interstices is ledoutwardly by force. In order to render possible a blisterfreeapplication with an angle of embrace of the label of about 60 to 180,-it is necessary in accordance with the realization of the inventionnot to arrange and hold the label on the face of the plunger adapted tothe hollow body, but to attach'the label in a stretched position on thesurface of the plunger. The advancement movement of the plunger takesplace when the inflation of the parison is almost finished, so that thelabel in the stretched position lies against the lower apex of theparison and then on further advancement movement is gradually wrappedaround the parison in the given angle of embrace; in this connectionduring the advancement movement of the plunger the air between theparison and the inner side of the label is led out of the bilateralwedge-shaped interstices via the mould parting line, without any airinclusions being able to form between the hollow body and the label inspite of large angle of embrace.

When on application of a label with a large angle of embrace of thistype the operation has to be effected starting from a strip-like filmfed into the mould in a rhythmical manner from which the individuallabels are to be stamped out by the plunger constructed as a cuttingtool, a problem arises in so far that on stamping out the label by theplunger the label is of necessity retracted from its stretched position,which is necessary for the blister-free application, by the cutting edgedirected perpendicularly to the longitudinal axis of the hollow body. Insuch a stamping out from the film the blister-free application with alarge angle of embrace is however impossible, since the label, before itcomes into contact with the inflated parison, is already in a positionof rest on the face of the plunger adapted to the shape of the hollowbody. Since a blister-free application is only ensured when the label instretched position is brought into contact with the inflated parison,the use of a film web offers the above-mentioned difficulties, thesurmounting of which is likewise the object of the invention. Thesedifficulties are obviated in accordance with the invention in that whenusing a film strip passing rhythmically through the mould, a film striphaving a width exceeding the width or length of the label is used and inthat the peripheral cut of the label perpendicular to the longitudinalaxis of the hollow body is effected firstly in the film and after thatthe perpendicular cut of the label lying parallel to the longitudinalaxis is effected. By the measure in accordance with the invention ofeffecting the peripheral cut of the label directed transversely to thelongitudinal axis of the hollow body in the film and only then ofundertaking the cuts lying in the direction of the longitudinal axis ofthe hollow body by the plunger moving out of its resilient position itis ensured that the label cut out of the film web remains in thestretched position until, as a result of the upward movement of theplunger, it comes into contact with the almost inflated parison. Onlywhen this measure in accordance with the invention is ensured, is ablister-free application of a label with large angle of embrace using afilm web possible.

When using ready cut labels, it is a feature of the invention that thelatter when lain in the mould engages at its edges lying in thedirection of the longitudinal axis of the hollow body and is depositedon the surface of the plunger. By the engagement of the ready cut labelat the edges lying in the direction of the hollow body longitudinal axisit is possible to apply the label in a stretched position onto the uppersurface of the plunger and to maintain it in this position until thestretched label, as a result of the upward movement of the plunger,comes into contact with the inflated parison.

The device for carrying out the method is characterized in that theplunger has at its faces adapted to the shape of the hollow body linkingsurfaces which accommodate the edges of the label lying in the directionof the axis of the hollow body, at said surfaces engaging the devicesserving for the flexible holding of the label. The seating of the labelon the plunger takes place on the surfaces linked to the rounding of theplunger, said surfaces either lie as horizontal surfaces in one planeand/or can be obliquely conically inclined to each other, where in thecase of the latter embodiment of the surfaces the application of thelabel onto the hollow body is rendered easy. The label is maintained inthe stretched position by devices engaging at the seating surfaces andas a result of the flexible holding on applying the label to the hollowbody is drawn off from these surfaces, where the edge areas are alsojoined to the hollow body, when the plunger arrives at its mould closureposition.

The devices serving to hold the label on the seating surfaces canconsist of perforations opening out in the seating surfaces and fed withvacuum intake air.

When using a strip-like film the device is characterized in that thereis provided in the guides of the plunger lying on both sides of the filmin the direction of movement a groove formed by a guide strip andcutting strip; said groove corresponding to the width of the foil andbeing above the cutting edge of the plunger in the resilient position.In this case it is essential that in the plunger guides having the guidegroove there are incorporated parallel to the lift direction of theplunger displaceable pins which are each reinforced at the plungerunderside by a compression spring or the like; said pins each having attheir upper ends a clamping member overlapping the receiving surface ofthe plunger and that there are secured at the plunger spring elementswhich on engagement with a collar arranged on the pins limit theclamping effect of the clamping member until the label is withdrawn fromthe latter and the plunger reaches the mould closure position with theclamping members. On upward movement of the plunger the label isseparated from the strip by the cutting edge of the plunger lying in thedirection of the longitudinal axis of the hollow body out of the filmstrip whose cuts are made transversely to the hollow body. In this waythe label with edge areas lying along the axis of the hollow body istensioned and held fast between the seating surfaces of the plunger andthe clamping members overlapping these. Directly before the plungerreaches its closure position the spring elements secured to the plungermeet in engagement with the collar of the pin and thus limit the widthof the clamping gap so that on further upward movement of the plungerthe labels can be withdrawn without damage from the clamping members.Only then, when the plunger has completely reached its closure positionis Y the force of the spring elements overcome so that the clampingmembers come to sit directly on the seating surface of the plunger andform a gapless blow mould. Instead of the clamping members there canwhen-using a film also be provided perforations which are under vacuumair intake and empty in the seating surfaces of the plunger. r

In order to effect the cuts to be made transversely to the hollow bodyaxis there can be arranged on the mould an additional device whicheffects the necessary cut directed at right angles before it enters themould, where two cuts following one after the other and directed atright angles must, of course, have a spacing which corresponds to thelength or width of the label.

In accordance with a further feature there can also be used a film stripin which the necessary cuts or stampings to be arranged transversely tothe hollow body longitudinal axis have already been made.

The shape of the label to be applied to the hollow body is notrestricted to a square or perpendicular shape; labels with roundedcomers can also be used. Furthermore labels which have an oval or roundshape can also be used; in this case the cuts perpendicular and parallelto the longitudinal axis of the hollow body are not rectilinear butcorrespond to the shape of the label as the case may be. Furthermore thelabels can be applied also from both sides onto the hollow body in sucha manner that there results a two-part label enveloping the whole hollowbody; in this case both parts of the blow mould are provided with aplunger to apply the label. In addition the invention is not restrictedto cylindrical hollow bodies; they can also be made conical orball-shaped.

The invention will be further described by way of examples withreference to the accompanying drawings, in which:

FIG. 1 shows a section through a device in accordance with the inventionusing a film strip;

FIG. 2 shows a transverse section along line A-B of FIG. 1 with the filmstrip;

FIG. 3 is a view in accordance with FIG. 2, in which a longitudinal cutof the film strip is made;

FIG. 4 is a view in accordance with FIG. 3 in which the label, held in astretched position, comes into contact with the almost inflated tubeparison;

FIG. 5 is a view in accordance with FIG. 2 in which the plunger is inthe mould closure position;

FIG. 6 is a schematic view with a film strip running in the longitudinaldirection of the hollow body;

FIG. 7 is a view in accordance with FIG. 4 in which the perforations arearranged, as holding device, impinged on with vacuum intake air emptyingin the seating surfaces of the plunger;

FIG. 8 is a schematic view in accordance with FIG. 6 with a film striprunning at right angles to the longitudinal axis of the hollow body;

FIG. 9 is a view of an engagement device for inserting ready cut labelsinto the blow mould;

FIG. 10 is a view in accordance with FIG. 2 using ready cut labels;

FIG. 11 is a view in accordance with FIG. 7 using ready cut labels; and

FIG. 12 is a view in accordance with FIG. 5 using ready cut labels.

FIGS. 1 to 8 show devices in accordance with the invention with a filmstrip, FIGS. 9 to 12 show a device in accordance with the invention witha ready cut label lain in the mould.

FIG. 1 shows one of the devices in section. It consists, in the normalmanner, of two mould halves l and 2 between which in the closureposition there is engaged a blow mandrel 3 which inflates a tube-shapedparison 4 of thermoplastic synthetic material which is taken up in themould; in the mould half 2 there is arranged a plunger 5 which can bemoved from a withdrawn position shown in FIG. 2 by means of apiston-cylinder-arrangement 6 to a mould closure position shown in FIG.5. The mould half 2 possesses an opening 7, through which strip 8 of asheet or film of weldable or adhesive material is introduced via rollers9 into the mould parting line. The plunger 5 possesses a face 10corresponding to the hollow body, the said face 10 adjoining, on bothsides, seating surfaces 11, on which, as FIG. 2 shows, the film strip 8lies. The width of the label corresponds to the width of the stampingplunger 5 with its seating surfaces. In the mould half 2 there arearranged on both sides guide strips 12 lying in the longitudinal axis ofthe parison 4; on said guide strips 12 there is arranged a strip 13which serves as a separator; on said strip 13 lies the cutting strip 14.The film possesses, as FIG. 2 shows, a greater width than the width ofthe label and is guided on both sides into the groove or channel formedby the strips 12, 13, 14. When, as FIG. 3 shows, the parison 4 isinflated to a certain extent the piston-cylinder-arrangement 6 comesinto operation and moves the plunger 5 out of its withdrawn positionaccording to FIG. 2 upwards, as shown in FIGS. 3 to 5. By this means,the label 15 is cut out of the film 8 with the requisite width by theouter edges of the seating surfaces 11 which serve together with thecutting strip 14 as cutting edges. On a further upward movement of theplunger 5, as FIG. 4 shows, the rigidly held label 15 comes into contactwith the lower apex of the parison 4 and is gradually during furtherinflation and during the further upward movement of the plunger 5brought into the final position shown in FIG. 5; in said position theplunger 5 has reached its mould closure position and the label 15. overits whole length lies at an envelopment of the in flated hollow body atan angle of about When, according to FIG. 2, the label is cut out fromthe film strip 8 the seating surfaces 11 of the plunger 5 bearing thelabel 15 (FIG. 3) in a taut or stretched condition come into contactwith clamping members 16 which overlap the seating surfaces 11 of theplunger 5 and engage the label 15 at its edges lying in the direction ofthe axis of the hollow body 4. The clamping effect between the members16 and the seating surfaces 11 is attained by the clamping members 16being secured to pins 17 which are arranged in the strips 12, l3, 14 inan upward displaceable manner. The pins are of reduced width over theirlower regions 19, forming collars 18. The regions 19 extend through theside flanges 20 of the plunger 5 and carry on their ends compressionsprings 21 which are compressed between the end of the region 19 and theunder side of the flanges 20. Below each collar 18 there is secured tothe upper side of the flange 20 a plate spring 22. The mode of operationof the pins 17 is as follows. When, according to FIG. 3, the label 15 iscut out-of the film strip 8 the plunger moves upward and comes intoengagement with the clamping members 16 which are taken by the plungerwith it on its further upward movement according to FIG. 4. In this waythe springs 21 become tensioned and exert a holding pressure on theclamping members 16, whereby the limitation of the clamping gap iseffected by the plate springs 22. In this way the label, held at itsedges by the clamping members, is so flexibly tensioned that on upwardmovement of the plunger 5 into the mould closure position, as FIGS. 4and 5 show, the label is drawn out of the gaps of the clamping members16 so that it lies completely on the surface of the parison 4 in themould closure position as shown in FIG. 5. On attainment of the mouldclosure position the force of the plate springs is overcome by theeffect of the piston-cyfinder-arrangement so that the gap given betweenthe clamping members 16 and the seating surfaces ll-of the plunger 5 iscompletely closed in order to prevent the formation of a gap'in theclosed mould. The corners of the label 15 can be slightly rounded offwhereby the label lies sunk in the hollow body.

The making of the necessary cuts transversely to the longitudinal axisof the hollow body must take place before the plunger 5 is moved outfrom its position shown in FIG. 2. In order to be able to make thesetransverse cuts before the making of the longitudinal cut by the plunger5 in the film strip 8, there is arranged in the mould half 2 a cuttingor stamping tool 23 which is moved upward by means of a lever 24 by anyappropriate actuation member, when the film 8 is at rest in the mould 2.The spacing of the cutting tool 23 from the front edge of the plungercorresponds to one label length or a multiple of the label length. Inorder to be able to adjust the cutting tool 23 to the requisite lengthof the label 15, it is held on the mould half 2 so that it istransversely displaceable.

FIGS. 6 and 7 show an embodiment in which the film strip 8 is guided inthe direction of the longitudinal axis of the hollow body 4 through themold 2. For the sake of clarity the portions of the foil stripprojecting above and below the mould are drawn in the plane of thedrawing, where the transverse cut is shown in the form of a stamping 25.Instead of the cut-out 25 a simple cut can also be carried out. The foilstrip 8 is transported in the direction of the arrow, the film strip 8being drawn in and waste edges 26 leave the mould l, 2 as shown.

FIG. 8 shows an embodiment corresponding to FIG. 6 with the differencethat the film strip 8, as in FIG. 1 is moved in the direction of thearrow perpendicularly to the longitudinal axis of the hollow body 4. Inthis case the cuts or stampings 25 to be made must first be undertakenon both sides along the edges of the film strip 8. The subsequent cutsin the direction of the longitudinal axis of the hollow body 4 arecarried out according to FIGS. 2 to by the plunger 5.

FIG. 7 shows a variant of the embodiment of FIGS. 2 to 5; here, insteadof the clamping members 16, there are arranged in the plunger 5 passages27 which open on to the seating surfaces 11. By using suction in thepassages 27 the edge regions of the label are held in position on theseating surfaces 11 of the plunger 5. Here, too, the edge regions arewithdrawn from the seating surfaces 11 on mould mould closure movementof the plunger 5 and brought to rest against the hollow body 4.

FIGS. 9 to 12 show a device in accordance with the invention with aready cut inserted label, FIG. 9 depicting an insertion device. As FIG.9 shows, a ready cut label 15 is removed at its opposite edges by agripping device 28 from a pile of labels (not shown). At both edges ofthe gripping device 28 are arranged elastic insert components 29 intowhich suction openings 30 open. The gripping device 28 is set down onthe uppermost label of the stack, whereupon the label is engaged by thevacuum openings 30 at or near its edges. The gripping member 28 is thenmoved into the opened mould in such a manner that the elastic inserts 29come into contact with the seating surfaces 1 l of the plunger 5. Afterthat the vacuum openings 30 are supplied with compressed air, by meansof which the label 15 is lain in stretched position onto the surfaces 11of the plunger 5. At the same time suction is applied to the bores 27 ofthe plunger 5 so that the label 15 is maintained in a taut or stretchedposition. FIGS. 10 to 12 show the mode of operation of the device with aready cut label, where the application of the label onto the parisontakes place in practically the same manner, as depicted in FIGS. 2 to 5.

I claim:

1. Apparatus for applying a label in the form of a piece of a thin filmof material capable of adhering to an article of a thermoplasticsynthetic resin material as the article is blow-moulded in a mould intothe form of ahollow bodx said apparatus com rising:

a plunger avmg a concavity herein presenting a concave facecorresponding to a portion of the inner periphery of the mould;

means carried by the plunger and disposed at the boundaries of saidconcavity for yieldably holding the edges of said piece of film andinitially yieldably maintaining the latter in a generally planardisposition and in a spanning relationship to said concavity with thecentral areas of the piece of film disposed in spaced relationship tosaid concave face; and

means for advancing said plunger toward said hollow body and into amould closing position in a direction generally perpendicularly of theplane of said piece of film, whereby the central areas of said piece offilm are first brought into contact with the hollow body and continuingadvancement of the plunger wraps the piece of film around the body andwithdraws its edges from said yieldable holding means.

2. Apparatus as set forth in claim 1 wherein said holding meanscomprises a plurality of ducts and means for applying a suction to saidducts.

3. Apparatus as set forth in claim 1 wherein said holding meanscomprises spring-biased clamping means.

4. Apparatus as set forth in claim 1 wherein is included means forcontinually supplying a strip of said film to the apparatus and meansfor cutting said piece out of the strip.

3. Apparatus as set forth in claim 1 wherein said holding meanscomprises spring-biased clamping means.

4. Apparatus as set forth in claim 1 wherein is included means forcontinually supplying a strip of said film to the apparatus and-meansforcutting said piece out of the strip.

5. Apparatus as claimed in claim 3, wherein the spring-biased clampingmeans comprises a clamping member connected to pins which extend throughthe plunger and spring elements arranged on the pins.

6. Apparatus as claimed in claim 5, and comprising spring elementsadapted to limit the clamping force on the label or plate.

1. Apparatus for applying a label in the form of a piece of a thin filmof material capable of adhering to an article of a thermoplasticsynthetic resin material as the article is blowmoulded in a mould intothe form of a hollow body, said apparatus comprising: a plunger having aconcavity therein presenting a concave face corresponding to a portionof the inner periphery of the mould; means carried by the plunger anddisposed at the boundaries of said concavity for yieldably holding theedges of said piece of film and initially yieldably maintaining thelatter in a generally planar disposition and in a spanning relationshipto said concavity with the central areas of the piece of film disposedin spaced relationship to said concave face; and means for advancingsaid plunger toward said hollow body and into a mould closing positionin a direction generally perpendicularly of the plane of said piece offilm, whereby the central areas of said piece of film are first broughtinto contact with the hollow body and continuing advancement of theplunger wraps the piece of film around the body and withdraws its edgesfrom said yieldable holding means.
 2. Apparatus as set forth in claim 1wherein said holding means comprises a plurality of ducts and means forapplying a suction to said ducts.
 3. Apparatus as set forth in claim 1wherein said holding means comprises spring-biased clamping means. 3.Apparatus as set forth in claim 1 wherein said holding means comprisesspring-biased clamping means.
 4. Apparatus as set forth in claim 1wherein is included means for continually supplying a strip of said filmto the apparatus and means for cutting said piece out of the strip. 4.Apparatus as set forth in claim 1 wherein is included means forcontinually supplying a strip of said film to the apparatus and meansfor cutting said piece out of the strip.
 5. Apparatus as claimed inclaim 3, wherein the spring-biased clamping means comprises a clampingmember connected to pins which extend through the plunger and springelements arranged on the pins.
 6. Apparatus as claimed in claim 5, andcomprising spring elements adapted to limit the clamping force on thelabel or plate.